Nickel alloys possessing controlled mechanical q properties



March 21, 1967 M. B. HAPP NICKEL ALLOYS POSSESSING CONTROLLED MECHANICAL Q PROPERTIES Filed Sept. 17, 1963 mz m:

0 'IVOINVHOBW /N VEN 7' 0R MARV/N B HAPP Patented Mar'. 2l, 1967 3,310,394 NICKEL ALLOYS POSSESSING ACOFJTROLMED MECHANICAL Q PROPERTIES Marvin B. Happ, Hingham, Mass., assigner to Raytheon Company, Lexington, Mass., a corporation of Delaware Filed Sept. 17, 1963, Ser. No. 309,430 5 Claims. (Cl. '7S-122) The present invention relates generally to metallic alloys and particularly to alloys of the nickel type having controlled mechanical Q properties. In addition, this invention relates to magnetostrictive alloys of the iron nickel type having controlled mechanical Q properties.

The present invention is based upon the discovery that controlled amounts of metallic elements, such as Al added nickel bearing alloys in a manner so as to form a precipitate with the nickel, provide predetermined and producible magnitudes of Q greater than about 2000 and as muchV as 40,000 or even greater. In the past metallic materials, such as titanium, have been added to nickel bearing alloys during the melting process in order to irnpart hardening. In addition, it is generally accepted that aluminum in substantial amounts is capable of promoting a similar type of hardening, individually or in combination with titanium. Aluminum has always, to the best of our knowledge, appeared as an uncontrolled impurity or residual element in the titanium when titanium is utilized to obtain hardening. Although the influence of these two elements and other elements upon the mechanical properties of nickel base alloys, such asrhardness, tensile strength, yield strength, ductility and elastic modulus have been studied and classified, not until the teachings of this invention has a relationship been established between precisely controlled percentages of aluminum and related elements which form Ni3X precipitates with nickel and the value of a reproducible mechanical Q for a particular nickel bearing alloy. X is defined as either one individual element or a combination of two or more elements which form an Ni3X precipitate. For example, elements identified as A, B, C, and D may be combined individually with nickel as NiaA, NiBB, etc. or in combination as Ni3 (A,B), Nia (A,B,C) etc.

It also has been discovered that for a precisely reproducible Q, X should be controlled to a tolerance of about il atomic percent under identical aging conditions.

. However, it has been found that the best results are obtained utilizing tolerances of i.05 percent for X. The mechanical Q of a material is dened as Af where fo isthe resonant frequency and Af is the one-half power (3db) bandwidth at resonance for a magnetostrictive material. Q is inversely proportional to the damping capacity of the alloy. A low valueV of Q describes an alloy having high internal friction, high heat loss, and a low energy transmission capability. A high Q material produces the opposite effect. Therefore, for good energy transmission characteristics, an alloy having a high Q is preferable to one having a low Q. For example, in magnetostrictive applications, such as in magnetostrictive alloy rod filter components and magnetostrictive alloy delay line components, Amaximum energy transfer and low energy loss is highly desirable. A reproducible Q, however, is always desirable. Additionally, in the precision spring art, and particularly in the iield of Watch springs, it is also highly desirable that there be high energy transmission and thus -low heat loss. This would permit smaller size springs to be utilized to perform the same function as larger springs are presently called to perform in present day watches.

Although it would appear to be a natural assumption that/alloy properties, such as hardness, tensile strength, yield strength, ductility, and the modulus of elasticity can be utilized to accurately predict Q, experimental evidence collected up to the present time has tended to disprove the possibility of there being any quantitative correlation. For example, Q tends to increase with hardness; however, identical hardness, tensile, or yield strength values obtained from different melts, which were processed under identical conditions, have been found to encom-y pass a rather broad Q distribution. This is due to the treating of aluminum and other materials which happen to form precipitates with the nickel as a residual element or impurity, rather than as an element to be precisely contQrolled in order to produce alloys having predetermined Accordingly, it is the principal object of this invention to provide a nickel bearing alloy having predetermined Q properties.

It is a further object to provide a method of forming anickel bearing alloy having predetermined, reproducible, and predictable Q properties. i

lt is an additional object of this invention to provide a magnetostrictive alloy having controlled Q properties.

It is a further object of this invention to provide an iron nickel alloy of the magnetostrictive type having high mechanical Q properties and accordingly, high energy transmission properties.

Other objects and advantages of the present invention will become apparent to those skilled in the art from the following description taken in conjunction with the accompanying drawings, wherein:

FIG. l illustrates the aect of varying the atomic percentage of aluminum in an iron-nickel-chromium-titaniurn-aluminum alloy to provide a predictable Q; and

FIG. 2 is a schematic diagram of a magnetostrictive filter assembly showing magnetostrictive rod components or elements comprised of the magnetostrictive alloys of this invention.

For the purpose of illustration, in order to more clearly set forth the novel features of the present invention, the characteristics of nickel bearing alloys alloyed with aluminum in controlled amounts for providing precisely controlled predictable and predetermined mechanical Qs will be discussed. It has been discovered that the addition of aluminum in an amount so as to obtain approximately of Ni in atomic percentage and 25% of aluminum in atomic percentage in a nickel bearing alloy will provide substantially a maximum Q for a given nickel bearing alloy. By reducing the amount of aluminum so as to reduce this ratio of Al to Ni in a nickel bearing alloy, it is then possible to vary the maximum obtainable mechanical Q in a predetermined manner. By so controlling the ratio of nickel to aluminum in atomic percentage, the Q of the material can be varied between substantially 2000 and 40,000 and possibly even higher.

Table I discloses iron nickel alloys showing predetermined controlled additions in atomic percentage of aluminum added to form an alloy having a predetermined Q. Column l shows the range of atomic percentages of material in an iron-nickel-aluminum alloy, column 2 shows Cr in atomic percentage added to an iron-nickelaluminum alloy and column 3 shows an iron-nickel-chromium-titanium-aluminum alloy.

Vbelow 1350 F. for periods of between 2-4 hours.

TABLE I.-NICKEL ALLO YS WITH (OlgROLLED ATOMIC PERCENTAGES Element FeNiAl, Atomic FeNiCrAl, Atomic FeNiCrTiAl, Atomic Percentage Percentage Percentage Balance Balance. Greater than 0 to 17%... Grezlxger than Oto 17%. do o. A1 Greater than 0 to 17% do Do.

Although these alloys disclosed in Table I Will provide mechanical Qs within the aforementioned range, the percentages given in Table I will not necessarily produce a nickel bearing `alloy having magnetostrictive properties.

There is shown in Table II magnetostrictive alloys of the FeNiCrTiAl type. In the alloys of column 1 the percentages of materials, and more particularly the controlled percentages of aluminum in a range of between .5 and 3.0% were used to prepare alloys forming an Ni3Al precipitate and having mechanical Q properties between 2,000 and upwards of 35,000. The alloys of columns 2 and 3 also disclose alloys having mechanical Q properties in the same range but which have had their atomic percentage of aluminum varied between .02 and 3% and between 1.6 and 3%, respectively. All of these alloys provide a magnetostrictive material which will exhibit exponentially increasing Q with the increased amount of aluminum. When the addition of aluminum is increased above approximately 3%, the Q of the material will no longer increase but remain constant. This is shown in the drawing wherein alloys having controlled percentages ofi aluminum between .6 atomic percent and 2.7 atomic percent exhibit this effect.

The following method or process was used in the preparation of alloys l, 2, and 3. Controlled atomic percentages of Fe, Ni, Cr, Ti, and Al are combined using vacuum melting to form a heat of the above ingredients where the titanium used has an aluminum impurity content less than .l atomic percent. This heat is then cast into ingot form. The ingot is forged above 1750 F. and is then solution annealed and water quenched. Cold reduction of approximately above but below 99% of its diameter, is then used to produce .a thin rod which exhibits preferred orientation of the crystal structure. It

ment on Q. It is to be noted that the higher the temperature of heat treatment, the higher the Q for a particular melt of the same percentage of constituents. It should also be noted that an exponential relationship exists between Q and the amount of Al in the FeNiCrTiAl alloy over a limited range of added Al. Also, it has lbeen observed that the log of Q increases linearly with increased atomic percent of Al. The rod, which has been heat treated, is then permitted to'furnace cool before being utilized as magnetostrictive filter rod component elements.

TABLE II.-MAGNETOSTRICTIVE FeNiCrTiAl ALLOYS 1 Remainder:

In addition to controlled additions of aluminum as previously set forth in Tables I and II, it is believed that other metals or elements having the characteristics of aluminum and further forming precipitates of the NigX type can be used as controlled elements in order to vary Q of the alloy by a predetermined amount. For example, it is believed columbium can be substituted for aluminum by the addition of controlled percentages -as shown in Table III to form an FeNiCb as shown in column 2 of Table III. Column 2 of Table III shows an FeNiCrCb alloy having controlled Q properties and Table III discloses an FeNiCrTiCb alloy having controlled Q properties.

TABLE IIL-NICKEL ALLO YS WITH CONTROLLED PERCENTA GES OF Cb has been found that a cold reduction or cold work of approximately 96.5% appears to provide the best results. The greater the percentage of cold Work, the higher the Q for the alloy material. The rod material of this alloy is then cut into filter component lengths dependent upon the frequency that is to be filtered. For example, a rod length of 1.920 inches corresponding to one wavelength at a frequency of 100 kc. is chosen in order to lter the second harmonic of this frequency. These individual lengths of rod are then aged in a furnace to a temperature or a series of different temperatures above 700 but A three hour aging treatment has produced the best results Furthermore, it is theorized that nickel bearing alloys having controlled percentages of molybedenum can be prepared in the manner as previously mentioned in order to obtain a nickel bearing alloy having controlled mechanical Q properties.

Table IV discloses the percentages of iron, nickel and the other elements including a range of controlled amounts of molybedenum to produce a controlled Q alloy. Additionally, it is believed that controlled amounts of Ta, Th, V, and W can be added in the same percentages as molybedenum as disclosed in Table IV to form a Ni3X precipitate to provide a nickel bearing alloy having conto date. The drawing shows the effect of the heat treattrolled Q properties.

TABLE IV.NICKEL ALLOYS WITH CONTROLLED ATOMIC PERCENT- AGES OF Ti It is also believed that the aforementioned controlled percentages of aluminum can be altered by the addition of controlled percentages of titanium -to produce a Ni3(AlTi) precipita-te wherein three atoms of titanium can replace two atoms of aluminum to form the aforementioned precipitate in order'to provide an alloy having controlled mechanical `Q properties in a range greater than V2,000 and as much as 40,000.

Alloys having Q properties wherein the range of 2,000 to 40,000 are particularly suitable for use in applications requiring materials having low internal friction properties. In addition, magnetostrictive alloys having Q properties in the range of 2,000 to 40,000 are particularly suitable for use as magnetostriotive rod elements for filters and spectrum analyzer devices.

For example, FIG. 2 shows a magnetostrictive rod element or component comprised of the magnetostrictive alloys of this invention in a schematic representation of a filter assembly suitable for use in spectrum analysis. The rod 10 is held at its nodal points by washers 13 and 14 mounted on supports 11 and 12, respectively. Supports 11 and 12 are inserted ina supporting block of material 20. The nodal points'deiine 1A wavelengths from the end of'a rod at any particular input signal frequency of operation.

A drive coil 15 is shown wound on one end of rod 10 and is connected to -an input signal source 16. A pick-01T coil is wound on the opposite end of the rod 10 and is connected to a load 18. Magnets 21 and 22 are positioned at opposite ends of rod 10 in order to magnetically bias and orient the magnetic domains in the rod. Both the input and pick-off coils a-re wound so as -to produce an electromechanical coupling wherein neither Winding is in contact with the rod.

Fur-thermore, magnetostrictive materials having a Q greater than 40,000 can `be microphonic and thus, are suitable for use in devices such as microphones or other sensing devices. These materials having Qs greater than 40,000 are particularly sensitive to frequencies in the acoustical range. Accordingly, magnetostrictive alloys of the type disclosed in this invention provide a means for producing devices requiring predetermined microphonic properties. Accordingly, it is desired that this invention not be limited except as defined by the appended claims.

What is claimed is:

1. An iron-nickel-chromium-titanium group metal alloy having .a predetermined mechanical Q, low internal friction, and low energy transmission loss; said alloy consisting essentially of nickel in amounts ranging from about 35-50 atomi-c percent, chromium in an effective amount greater than 0 but less than or equal to about 17 atomic percent, titanium in an eifective amount greater than 0 but less than or equal to about 17 atomic percent, and a metal material X selected from a group consisting of aluminum, columbium, molybdenum, tantalum, thorium, vanadium or tungsten ranging in precontrolled amounts greater than 3 but less than or equal to about 17 atomic percent where the X metal material forms an Ni3X precipitate with nickel, and the remainder iron; said Q of said alloy increasing exponentially to about 35,000 with the addition of X in said aforementioned amounts.

2. A magnetostrictive filter or delay line component having a predetermined mechanical Q, said component consisting essentially of nickel in amounts ranging from about 35-50 atomic percent, chromium in an effective amount greater than 0 but less than or equal to about -17 Iatomi-c percent, titanium in an effect-ive amount greater than 0 lbut less than or equal to about 17 atomic percent, and a metal material X selected from a group consisting of aluminum, columbium, molybdenum, tantalum, thorium, vanadium or tungsten ranging in precontrolled amounts greater than 3 but less than or equal to about 17 atomic percent, where the X metal material forms an Ni3X precipita-te with nickel; and the remainder iron.

3. An iron-nickelchromium-titanium-aluminum group metal alloy having magnetostrict-ive properties; a predetermined mechanical Q ranging up as high as 35,000-, low internal friction, and low energy transmission loss; said alloys consisting essentially of nickel in amounts of between about 40-42 atomic percent, chromium in an amount between about 5-6 atomic percent, titanium in an amount between 3.0 and 3.6 atomic percent, and aluminum in precontrolled toleranced amounts in a range between about 1.6` and 3.0 atomic percent, and the remainder iron.

4. A magnetostrictive alloy lof the aluminum-ironnickel-chromium-titanium type having a range of controlled mechanical Q properties up to about 40,000, said alloy consisting essentially of nickel in an amount ranging from about 40-42 atomic percent, chromium in an amount ranging between about 5.0 and 6.0 atomic percent, titanium lin effective amounts between about 3.0 and 3.6 atomic percent, and controlled tolerances of atomic percent of `aluminum of between about 1.6 and 3.0 atomic percent, and the remainder of iron and; said alloy having a mechanical yQ which increases exponentially with increased aluminum within said range of Q.

5. A magnetostrictive alloy of the `aluminum-nickeliron-chromium-titanium type having precontrolled range of mechanical Qs up -to about 40,000, said magnetostrictive alloy consisting essentially of about 41 atomic percent of nickel, about 5.5 atomic percent chromium, about 3.3 Iatomic percent titanium, precisely controlled tolerances of amounts of aluminum between about 1.6 and 3.0 atomic percent, and the remainder iron, said alloy having a critically dependent value -of mechan-ical Q which increases exponentially with increased amounts of aluminum.

References Cited by the Examiner UNITED STATES PATENTS 2,719,084 9/ 1955 Countis 75-123 3,015,558 1/1962 Grant 75-171 3,021,211 2/1962 Flinn 75-170 3,067,030 12/1962 Dunn 75-171 3,069,258 12/1962 Haynes.

3,117,862 1/1964 `Clark 14S-31.55 X 3,145,124 8/1964 Hignett 75-170 `HYLAND BIZOT, Primary Examiner.

DAVID L. RECK, Examiner.

P. WEINSTEIN, Assistant Examiner. 

1. AN IRON-NICKEL-CHROMIUM-TITANIUM GROUP METAL ALLOY HAVING A PREDETERMINED MECHANICAL Q, LOW INTERNAL FRICTION, AND LOW ENERGY TRANSMISSION LOSS; SAID ALLOY CONSISTING ESSENTIALLY OF NICKEL IN AMOUNTS RANGING FROM ABOUT 35-50 ATOMIC PERCENT, CHROMIUM IN AN EFFECTIVE AMOUNT GREATER THAN 0 BUT LESS THAN OR EQUAL TO ABOUT 17 ATOMIC PERCENT, TITANIUM IN AN EFFECTIVE AMOUNT GREATER THAN 0 BUT LESS THAN OR EQUAL TO ABOUT 17 ATOMIC PERCENT, AND A METAL MATERIAL X SELECTED FROM A GROUP CONSISTING OF ALUMINUM, COLUMBIUM, MOLYBDENUM, TANTALUM, THORIUM, VANADIUM OR TUNGSTEN RANGING IN PRECONTROLLED AMOUNTS 